Nonviral vectors have emerged as promising delivery agents in gene therapy due to several problems associated with viral systems. The structure-function relationships of a series of polycations used for gene delivery will be investigated by synthesizing and testing in vitro a series of carbohydrate-based polymers with differing structures for toxicity and gene delivery efficiency. This study will provide insights into the properties of polymeric vectors such as: the role of charge separation, the hydration effects of the polymer backbone, and the significance of steric hindrance around the charge center in the formation of the DNA-polymer complexes. In addition, by accurately obtaining the binding constants for the polymer-DNA complexes, the role that binding strength has on gene delivery efficiency and toxicity may be more thoroughly understood. The results of this study will aid in the design of future generations of nonviral vectors for the delivery of therapeutic genes.